1. Field of the Invention
The present invention relates to a biologically active substance recovered from the mycelium and fruit body of Agaricus blazei; and a process of preparing the biologically active substance.
2. Description of the Prior Art
Agaricus blazei is a mushroom of Basidiommycetes from Brazil. It has been known that the mushroom is very effective for treating cancer and other adult diseases. In recent years, an artificial method for cultivating the mushroom has been developed, but because of the difficulty in the cultivation, currently, the supply is far lower than the growing demand.
Alternatively, research has been conducted regarding Agaricus blazei from a medical and nutritional standpoint, reporting that the principally effective component of the mushroom is β-glucan, one of the polysaccharides. β-glucan has such high immune activation potency that the glucan can activate immune cells (for example, natural killer cells) thereby attacking cancer cells and killing the cells. It has been known that β-glucan is also present in mushrooms other than Agaricus blazei such as shiitake (Cortinellus shiitake) and maitake. 
Renntinan extracted from shiitake as well as crestin extracted from kawaratake have been formulated as anti-cancer agents. Some current research has suggested that Agaricus blazei is a mushroom with the highest anti-cancer action.
Methods for extracting effective polysaccharides such a β-glucan from Agaricus blazei have been proposed conventionally (for example, Japanese Patent Disclosure No. 1-67195). Because the content of β-glucan is very low in Agaricus blazei, however, a great amount of Agaricus blazei is required, to recover a given amount of the extract. Furthermore, Japanese Patent Disclosure No. 5-268905 describes a method for extracting extractable components from whole Agaricus blazei by using an enzymatic agent. In this method, an extract solution with flavor like matsutake (Armillaria matsutake) can be recovered, through the action of enzymatic agents containing endo-1,4-β-glucanase, xylanase and endo-1,3-β-glucanase on Agaricus blazei. 
By the method for extracting such extractable components, however, β-glucan contained in the whole Agaricus blazei or β-glucan recovered during the intermediate stage of treating the mushroom may further be decomposed to generate cellobiose and glucose, because the enzymatic agent containing β-glucanase is utilized by the method.